Substrate Holder, Stage Apparatus, and Exposure Apparatus

ABSTRACT

An object of the invention is to hold a substrate with satisfactory flatness, even at a circumferential edge part that surrounds a suction space. The invention is equipped with a circumferential edge part ( 33 ) that surrounds a suction space ( 38 ), and a first support part ( 34 ) that is provided in the suction space ( 38 ) and that supports a substrate. Furthermore, the invention is equipped with a second support part ( 7 ) that extends from the circumferential edge part ( 33 ) to the first support part ( 34 ) and that supports the substrate.

TECHNICAL FIELD

The present invention relates to a substrate holder, a stage apparatus,and an exposure apparatus, and more particularly relates to, forexample, a substrate holder and a stage apparatus that are ideal forvacuum chucking a substrate, such as a wafer, as well as an exposureapparatus that comprises this substrate holder.

The disclosure of the following priority application is herebyincorporated by reference in its entirety: Japanese Patent ApplicationNo. 2004-253978, which was filed on Sep. 1, 2004.

BACKGROUND ART

Projection type exposure apparatuses and laser repair apparatuses areknown examples of apparatuses that fabricate, for example, semiconductorwafers (hereinbelow, called wafers) used in the manufacture ofsemiconductor devices as well as substrates, such as glass substrates.

In the case of a projection type exposure apparatus, a projection lens(projection optical system) is provided for imaging and projecting acircuit pattern of a reticle onto a substrate front surface at aprescribed magnification. This projection lens needs to have highresolving power, particularly in the case of a reduction projectionlens, while simultaneously securing a large projection area, and,consequently, the NA (numerical aperture) has increased year by yearwhile the depth of focus has attendantly decreased.

Consequently, with an exposure apparatus as described above, thesubstrate must be precisely planar in order to prevent resolutiondefects that are caused by the mispositioning of the substrate frontsurface with respect to the focal point position, and thereby to form afine circuit pattern; therefore, a substrate holder is used that vacuumchucks the abovementioned substrate and performs a correction to flattenthe substrate within a prescribed plane.

Patent Document 1 cites an example of a prior art substrate holderwherein support pins are provided that support a wafer inside a suctionchamber that is surrounded by an outer circumferential wall; therein,the wafer is mounted so that its outer circumferential part covers theouter circumferential wall of a wafer chuck (substrate holder), whichvacuum chucks the wafer by negatively pressurizing the suction chamberin a state wherein the wafer is chucked and flat with respect to theupper surfaces of the support pins and the outer circumferential wall.In addition, with this type of substrate holder, the suction forceapplied by the suction apparatus to negatively pressurize the suctionchamber acts upon the inner flat surface of the wafer, but not upon itsouter circumferential part, which causes such to warp even when using awafer that has satisfactory flatness.

Accordingly, Patent Document 1 discloses a technology that employs theVenturi effect to cause a force to act in a direction that preventswarpage of the wafer's outer circumferential part by providing a suctiongroove, which externally draws a gas into the suction chamber, to theouter circumferential wall.

Patent Document 1: Japanese Patent No. 3,205,468

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

Nevertheless, the related art discussed above has the following types ofproblems.

When forming the suction groove in the outer circumferential wall, thereis a problem in that it is necessary to strictly control the size of thesuction groove in order to control the force that prevents warpage,which makes alignment troublesome.

In addition, there is also a concern that when liquid is filled betweenthe wafer and the projection optical system and a pattern is exposed onthe wafer through this liquid, i.e., when so-called immersion exposureis performed, the liquid will infiltrate the suction chamber from thesuction groove.

In addition, to reduce the effect of dust located between the wafer andthe support pins, the size of the upper surfaces of the support pinshave shrunk in recent years, thereby creating a tendency for the supportpin tips to bite into the rear surface of the wafer, which in turn tendsto increase warpage (waviness) of the wafer between the location of thewafer that is supported by the outer circumferential wall and thelocation that is supported by the support pins.

Waviness of an exposure slit (a slit through which exposure illuminationlight is projected), which is for transferring the pattern to the wafer,is compensated for by correcting the position of the wafer front surfaceby driving (e.g., leveling) a wafer stage so that the flatness of theslit is within a prescribed value; however, compensating for wavinessusing the stage drive is problematic because, for example, wavinessincreases if the exposure slit is at a position where it straddles theouter circumferential wall.

The present invention was created considering the abovementioned points,and it is an object of the present invention to provide a substrateholder that can hold a substrate so that its flatness is stable andsatisfactory even at a circumferential edge part that surrounds asuction space, as well as a stage apparatus and an exposure apparatus.

Means for Solving the Problem

To achieve the abovementioned object, the present invention adopts thefollowing constitution that corresponds to FIG. 1 through FIG. 8, whichshow the embodiments.

A substrate holder of the present invention is a substrate holder (PH)that comprises: a circumferential edge part (33) that surrounds asuction space (38); and a first support part (34) that is provided inthe suction space (38) and that supports a substrate (P); comprising asecond support part (7) that extends from the circumferential edge part(33) to the first support part (34) and that supports the substrate (P).

Accordingly, with the substrate holder of the present invention, thesecond support part (7) is linear (a projection) from thecircumferential edge part (33) to the first support part (34) andsupports the substrate (P) at the circumferential edge part (33), whichmakes it possible to suppress waviness and warpage that occurs betweenthe circumferential edge part (33) and the first support part (34).

In addition, the stage apparatus of the present invention is a stageapparatus (PST) that holds and moves a substrate (P), comprising: theabovementioned substrate holder (PH), which serves as a substrate holderthat holds the substrate (P).

Accordingly, with the stage apparatus of the present invention, it ispossible to hold the substrate (P) and move it to a prescribed positionwithout causing major waviness or warpage of the substrate (P) at thecircumferential edge part (33) of the substrate holder (PH).

Furthermore, an exposure apparatus of the present invention is anexposure apparatus that uses a stage apparatus to expose a substrate (P)with a pattern, wherein the abovementioned stage apparatus (PST) is usedas the stage apparatus.

Accordingly, with the exposure apparatus of the present invention, thesubstrate (P) can be moved without causing major waviness or warpage ofthe substrate (P) at the circumferential edge part (33) of the substrateholder (PH), which makes it possible to transfer the pattern to thesubstrate (P) with a prescribed transfer accuracy.

Furthermore, to facilitate understanding, the present invention wasexplained by referencing corresponding symbols in the drawings, whichshow one embodiment, but the present invention is of course not limitedthereto.

EFFECTS OF THE INVENTION

The present invention can support a substrate with a stable andsatisfactory flatness, and can therefore form a high resolution patternthereon.

In addition, when performing an exposure by using a liquid, the presentinvention prevents the infiltration of the liquid between the substrateand the substrate holder, which makes it possible to stably perform theexposure process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a substrate bolder according to one embodimentof the present invention.

FIG. 2 is a partially enlarged view of the substrate holder holding asubstrate.

FIG. 3 is a plan view of the substrate holder according to the secondembodiment of the present invention.

FIG. 4 is a schematic block diagram that shows one embodiment of anexposure apparatus of the present invention.

FIG. 5 is a schematic block diagram that shows a liquid supply mechanismand a liquid recovery mechanism.

FIG. 6 is a plan view of a substrate stage.

FIG. 7 is a cross sectional view of principal parts and shows oneembodiment of the substrate stage according to the present invention.

FIG. 8 is a schematic block diagram that shows another embodiment of theexposure apparatus.

FIG. 9 is a flow chart diagram that shows one example of a semiconductordevice fabrication process.

DESCRIPTION OF THE REFERENCE SYMBOLS

-   EX: Exposure apparatus-   P: Substrate-   PH: Substrate holder-   PST: Substrate stage (stage apparatus)-   1: Liquid-   7: Rib shaped support part (second support part)-   33: Circumferential wall part (circumferential edge part)-   34: Support part (first support part)-   38: Suction space-   52: Substrate stage (substrate holder)-   55A: Reflecting surface (reflecting part)

BEST MODE FOR CARRYING OUT THE INVENTION

The following explains embodiments of a substrate holder, a stageapparatus, and an exposure apparatus of the present invention,referencing FIG. 1 through FIG. 9.

[Substrate Holder] <First Embodiment>

Fit, a first embodiment of the substrate holder according to the presentinvention will be explained, referencing FIG. 1 and FIG. 2. FIG. 1 is aplan view of the substrate holder and FIG. 2 is a partially enlargedview that shows the substrate holder holding a substrate P.

A substrate holder PH vacuum chucks the substrate P and comprises: asubstantially discoidal base part 35; a circumferential wall part 33(circumferential edge part), which is provided along a circumferentialedge of the base part 35 so that it is upright, that supports a rearsurface PC of the substrate P on the inner side of the outercircumference of the substrate P; a plurality of support parts 34 (firstsupport parts) that are evenly disposed in a suction space 38, which ison the inner side of and surrounded by the circumferential wall part 33,and that supports the substrate P; and a plurality of rib shaped supportparts 7 (second support parts), which extend from the circumferentialwall part 33 toward the support parts 34, that linearly supports thesubstrate P. Furthermore, in the present embodiment as shown in FIG. 2,the height of each of the support parts 34 is the same as the height ofeach of the rib shaped support parts 7. Furthermore, the height of eachof the support parts 34 and of each of the rib shaped support parts 7 isthe same as the height of the circumferential wall part 33.

The support parts 34 constitute a pin chuck (refer to FIG. 2) and aretrapezoidal in a cross sectional view; furthermore, each of the supportparts 34 has an upper end surface 34A, the diameter of which is minute,that holds the rear surface PC of the substrate P.

The rib shaped support parts 7 are each formed so that they extend alongthe X axial direction and are disposed on both sides of the substrateholder PH in the X axial directions and are spaced apart at intervals inthe Y axial directions. In addition, the rib shaped support parts 7 areformed so that one end of each is connected to the circumferential wallpart 33; furthermore, the lengths of the rib shaped support parts 7extending from the circumferential wall part 33 to the support part 34vary so that the tips of their other ends form a zigzag shape and do notline up linearly or arcuately. Furthermore, the support surface area ofeach of the rib shaped support parts 7 that supports the substrate P isset larger than the support surface area of each of the support parts 34that supports the substrate P (to facilitate understanding, FIG. 2 showsthe surface area of each of the upper end surfaces 34A of the supportparts 34 larger than it actually is).

Furthermore, the substrate holder PH is manufactured by, for example,sandblasting or etching a ceramic material to remove portions that donot include the circumferential wall part 33, the support parts 34, andthe rib shaped support parts 7. In other words, the substrate holder PHis constituted so that the circumferential wall part 33, the supportparts 34, and the rib shaped support parts 7 are integrally formed onthe base part 35 from a ceramic material.

In addition, the substrate holder PH comprises a suction apparatus 40that negatively pressurizes the suction space 38, which is surrounded bythe circumferential wall part 33. The suction apparatus 40 comprises: aplurality of suction ports 41, which are provided to an upper surface ofthe base part 35 of the substrate holder PH; a vacuum part 42, whichincludes an externally provided vacuum pump; and a passageway 43, whichis formed inside the base part 35 and connects the vacuum part 42 toeach of the suction ports 41. The suction ports 41 are provided atprescribed locations on the upper surface of the base part 35 that aredifferent from the locations of the support parts 34. The suctionapparatus 40 is constituted so that it negatively pressurizes thesuction space 38 by suctioning the gas (air) inside the suction space38, which is formed so that it is surrounded by the circumferential wallpart 33, the base part 35, the support parts 34, and the substrate Psupported on the rib shaped support parts 7.

With the substrate holder PH constituted as described above, after thesubstrate P is mounted on the circumferential wall part 33, the supportparts 34, and the rib shaped support parts 7, the suction space 38 isnegatively pressurized by the operation of the vacuum part 42 of thesuction apparatus 40, and the rear surface PC of the substrate P isthereby vacuum chucked to the circumferential wall part 33, the supportparts 34, and the rib shaped support parts 7.

At this time, the negative pressure suction force from the suctionapparatus 40 acts upon an inner flat surface of the substrate P, whichis supported by the support parts 34, but does not act upon thecircumferential edge part of the substrate P, which is supported by thecircumferential wall part 33; however, the negative pressure suctionforce does act upon the surroundings of the rib shaped support parts 7,which extend from the circumferential wall part 33 to the support parts34, and, consequently, warpage and waviness that arise in the substrateP in the vicinity of the circumferential wall part 33 can be suppressed.In addition, although the rib shaped support parts 7 linearly supportthe substrate P, they are rib shaped and thus the area of their surfacesthat contacts the wafer does not greatly increase; therefore, the ribshaped support parts 7 are not affected by dust.

Accordingly, with the present embodiment, it is possible to support thesubstrate P with satisfactory flatness even in the vicinity of thecircumferential wall part 33. In addition, in the present embodiment,because the substrate P also makes contact with and is supported by thecircumferential wall part 33, it is not necessary to strictly controlthe size of the gap of the suction groove, as in the case wherein theVenturi effect is employed; in addition, it is possible to avoid theinfiltration of liquid into the suction space 38 and to maintain stablevacuum chucking of the substrate P even when performing immersionexposure. Furthermore, in the present embodiment, the lengths of the ribshaped support parts 7 that extend toward the support parts 34 arevaried, and therefore, even if the tip parts of the rib shaped supportparts 7 are arrayed, for example, linearly or arcuately, it is possibleto exclude the possibility that the plurality of rib shaped supportparts 7 will function as a virtual circumferential wall part andunfortunately cause warpage of the substrate P, and it is therefore alsopossible to more reliably support the substrate P flatly. Namely, thepositions (boundary positions) where the support of the substrate Pswitches between the rib shaped support parts 7 and the support parts 34are not all the same, and therefore the flatness of the substrate P doesnot degrade at these boundary positions.

In addition, with the substrate holder PH of the present embodiment, thecircumferential wall part 33, the support parts 34, and the rib shapedsupport parts 7 are integrally formed, and it is therefore possible tosimplify the fabrication process as compared with the case wherein eachof the support parts are separately formed; furthermore, forming thesupport parts integrally contributes to the improvement of productionefficiency, and also makes it possible to easily form the supportsurfaces of the substrate P so that they are flush with one another andto support the substrate P with a more satisfactory flatness. Inparticular, in the substrate holder PH according to the presentembodiment, the rib shaped support parts 7 are provided on both sides ofthe substrate holder PH in the X axial directions, and extend in the Xaxial directions; therefore, when performing a scanning exposure(discussed later), even if the longitudinal directions of an exposureslit ES (shown by the chain double-dashed line in FIG. 1) are set to theX axial directions and an exposure is performed at a position whereinone end part of the exposure slit ES in the X axial directions straddlesthe circumferential wall part 33, it is possible to suppress theoccurrence of warpage and waviness in the substrate P within theexposure slit ES.

Second Embodiment

Continuing, the second embodiment of the substrate holder according tothe present invention will now be explained, referencing FIG. 3.

Constituent elements in this figure that are the same as those in thefirst embodiment shown in FIG. 1 and FIG. 2 are assigned the samesymbols.

In the substrate holder PH according to the second embodiment, ribshaped support parts 7A, which support the substrate P, are providedradially; furthermore, one end of each of the rib shaped support parts7A is connected to the circumferential wall part 33, and the other endof each extends toward the support parts 34. The support surface areawherein these rib shaped support parts 7A support the substrate P isalso set larger than the support surface area wherein the support parts34 supports the substrate P. In addition, in the present embodiment aswell, the lengths of at least adjacent rib shaped support parts 7A,which extend toward the support parts 34, vary. Other aspects of theconstitution of the present embodiment are the same as theabovementioned first embodiment.

In addition to obtaining the same operation and effect of the firstembodiment, the present embodiment makes it possible to support thesubstrate P with satisfactory flatness in any direction in the vicinityof the circumferential wall part 33. For example, as shown in FIG. 3,even if the longitudinal directions of the exposure slit ES is set tothe Y axial directions, it is possible to suppress the occurrence ofwarpage and waviness in the substrate P within the exposure slit ES.Consequently, it is possible to relax the positioning accuracy of thesubstrate holder PH about the Z axis, and thereby to lessen the workneeded for positioning.

Stage Apparatus and Exposure Apparatus

Continuing, the stage apparatus, which comprises the abovementionedsubstrate holder PH, and the exposure apparatus, which comprises thestage apparatus that serves as a substrate stage, will now be explained,referencing FIG. 4 through FIG. 7.

An exposure apparatus EX shown in FIG. 4 comprises: a mask stage MSTthat supports a mask M; a substrate stage PST that supports a substrateP via the abovementioned substrate holder PH; an illumination opticalsystem IL that illuminates the mask M, which is supported by the maskstage MST, with exposure light EL of the exposure slit ES; a projectionoptical system PL that projects and exposes a pattern image of the maskM illuminated by the exposure light EL onto the substrate P that issupported by the substrate stage PST, which serves as the stageapparatus; and a control apparatus CONT that provides overall control ofthe operation of the entire exposure apparatus EX.

The exposure apparatus EX of the present embodiment is a liquidimmersion type exposure apparatus that applies the liquid immersionmethod to substantially shorten the exposure wavelength, improve theresolution, as well as substantially increase the depth of focus, andcomprises a liquid supply mechanism 10 that supplies a liquid 1 betweenthe projection optical system PL and the substrate P, and a liquidrecovery mechanism 20 that recovers the liquid 1 on the substrate P. Inthe present embodiment, pure water is used as the liquid 1. At leastduring the transfer of the pattern image of the mask M onto thesubstrate P, the exposure apparatus EX forms an immersion area AR2 withthe liquid 1, which is supplied by the liquid supply mechanism 10, on atleast one part of the substrate P that includes a projection area AR1 ofthe projection optical system PL.

Specifically, the exposure apparatus EX fills the space between anoptical element 2 at the tip part of the projection optical system PLand the front surface (exposure surface) of the substrate P with theliquid 1, projects the pattern image of the mask M onto the substrate Pthrough the projection optical system PL and through the liquid 1between this projection optical system PL and the substrate P, andthereby exposes the substrate P.

Here, the present embodiment explains an example of a case of using ascanning type exposure apparatus (a so-called scanning stepper) as theexposure apparatus EX that exposes the substrate P with the patternformed on the mask M, while synchronously moving the mask M and thesubstrate P in mutually different orientations (reverse directions) inthe scanning direction. In the following explanation, the directionsthat coincide with an optical axis AX of the projection optical systemPL are the Z axial directions, the directions in which the mask M andthe substrate P synchronously move (in the scanning directions) withinthe plane perpendicular to the Z axial directions are the X axialdirections, and the directions (non-scanning directions) perpendicularto the Z axial directions and the Y axial directions are the Y axialdirections. In addition, the directions about the X, Y and Z axes arethe θX, θY and θZ directions, respectively. Furthermore, “substrate”herein includes a semiconductor wafer coated with a photoresist, whichis a photosensitive material, and “mask” includes a reticle wherein adevice pattern, which is reduction projected onto the substrate, isformed.

The illumination optical system IL illuminates the mask M, which issupported by the mask stage MST, with the exposure light EL, andcomprises, for example: an exposure light source; an optical integratorthat uniformizes the intensity of the luminous flux emitted from theexposure light source; a condenser lens that condenses the exposurelight EL from the optical integrator; a relay lens system; and avariable field stop that sets an illumination region, which is on themask M and is illuminated by the exposure light EL, to be slit shaped.The illumination optical system IL illuminates the prescribedillumination region on the mask M with the exposure light EL, which hasa uniform luminous flux intensity distribution. Examples of light thatcan be used as the exposure light EL emitted from the illuminationoptical system IL include: deep ultraviolet light (DUV light), such asKrF excimer laser light (248 nm wavelength) and the bright lines (g, h,and i lines) in the ultraviolet region emitted from, for example, amercury lamp; and vacuum ultraviolet light (VUV light), such as ArFexcimer laser light (193 nm wavelength) and F₂ laser light (157 nmwavelength). ArF excimer laser light is used in the present embodiment.As discussed above, the liquid 1 in the present embodiment is purewater, and the exposure light EL can transmit therethrough even if it islight from an ArF excimer laser. In addition, deep ultraviolet light(DUV light), such as KrF excimer laser light (248 nm wavelength) and thebright lines (g, h, and i lines) in the ultraviolet region, can alsotransmit through pure water.

The mask stage MST supports the mask M and is two dimensionally movablein the plane perpendicular to the optical axis AX of the projectionoptical system PL, i.e., in the XY plane, and is finely rotatable in theθZ directions. A mask stage drive apparatus MSTD, such as a linearmotor, drives the mask stage MST. The control apparatus CONT controlsthe mask stage drive apparatus MSTD. Movable mirrors 50 are provided onthe mask stage MST. In addition, a laser interferometer 51 is providedat a position opposing each movable mirror 50. The laser interferometers51 measure in real time the position in the two dimensional directionsand the rotational angles of the mask M on the mask stage MST, andoutputs these measurement results to the control apparatus CONT. Thecontrol apparatus CONT drives the mask stage drive apparatus MSTD basedon the measurement results of the laser interferometers 51, therebypositioning the mask M, which is supported by the mask stage MST.

The projection optical system PL projects and exposes the pattern of themask M onto the substrate P with a prescribed projection magnificationβ, and comprises a plurality of optical elements, which includes theoptical element 2 (lens) provided at the tip part of the projectionoptical system PL on the substrate P side, and this plurality of opticalelements is supported by a lens barrel PK. In the present embodiment,the projection optical system PL is a reduction system that has aprojection magnification β of, for example, ¼ or ⅕. Furthermore, theprojection optical system PL may also be a unity magnification system oran enlargement system In addition, the optical element 2 at the tip partof the projection optical system PL of the present embodiment isprovided so that it is attachable and detachable (replaceable) to andfrom the lens barrel PK, and the liquid 1 of the immersion area AR2contacts the optical element 2.

The optical element 2 is made of fluorite. Because fluorite has a strongaffinity for water, the liquid 1 can adhere to substantially the entiresurface of a liquid contact surface 2 a of the optical element 2.Namely, because the liquid 1 (water) supplied in the present embodimenthas a strong affinity for the liquid contact surface 2 a of the opticalelement 2, the liquid contact surface 2 a of the optical element 2 andthe liquid 1 have strong adhesion characteristics, and therefore theoptical path between the optical element 2 and the substrate P can bereliably filled with the liquid 1. Furthermore, the optical element 2may be made of quartz, which also has a strong affinity for water. Inaddition, the liquid contact surface 2 a of the optical element 2 may begiven hydrophilic (lyophilic) treatment in order to further increase itsaffinity with the liquid 1. In addition, because the vicinity of the tipof the lens barrel PK contacts the liquid 1 (water), at least thatvicinity is made of a metal, such as Ti (titanium), that is rustresistant.

The substrate stage PST supports the substrate P and comprises: asubstrate table 52 that holds the substrate P via the substrate holderPH discussed above; an XY stage 53 that supports the substrate table 52;and a base 54 (base plate) that supports the XY stage 53. A substratestage drive apparatus PSTD, such as a linear motor, drives the substratestage PST. The control apparatus CONT controls the substrate stage driveapparatus PSTD. Driving the substrate table 52 controls the position ofthe substrate P, which is held on the substrate table 52, in the Z axialdirections (the focus position) and in the θX and θY directions. Inaddition, driving the XY stage 53 controls the position of the substrateP in the X and Y directions (the position in the directionssubstantially parallel to the image plane of the projection opticalsystem PL). In other words, the substrate table 52 functions as a Zstage that controls the focus position and the inclination angles of thesubstrate P via the substrate holder PH, and aligns the front surface ofthe substrate P with the image plane of the projection optical system PLby using an auto focus system and an auto leveling system; further, theXY stage 53 positions the substrate P in the X axial directions and theY axial directions. Furthermore, the substrate table 52 and the XY stage53 may of course be integrally provided.

Movable mirrors 55 are provided on the substrate stage PST (substratetable 52). In addition, a laser interferometer 56 is provided at aposition opposing each movable mirror 55. The position in the twodimensional directions and the rotational angles of the substrate P onthe substrate stage PST are measured in real time by the laserinterferometers 56, and these measurement results are outputted to thecontrol apparatus CONT. The control apparatus CONT drives the substratestage drive apparatus PSTD based on the measurement results of the laserinterferometers 56, and thereby positions the substrate P supported onthe substrate stage PST.

Furthermore, each of the movable mirrors 55 may be formed by mirrorpolishing a side surface of the substrate stage PST (substrate table52), and the height of each of the movable mirrors 55 may be at the sameas the height of the substrate P (wafer).

In addition, a plate part 30, which surrounds the substrate P, isprovided on the substrate stage PST (substrate table 52). The plate part30 and the substrate table 52 are integrally provided, and a recessedpart 32 is formed on the inner side of the plate part 30. Furthermore,the plate part 30 and the substrate table 52 may be separately provided.The substrate holder PH, which holds the substrate P, is disposed in therecessed part 32 (refer to FIG. 7). The plate part 30 has a flat surface31 (flat part) that is at a height that is substantially the same as afront surface PA of the substrate P, which is held by the substrateholder PH that is disposed in the recessed part 32.

The liquid supply mechanism 10 supplies the prescribed liquid 1 to thesubstrate P and comprises: a first liquid supply part 11 and a secondliquid supply part 12 that are capable of supplying the liquid 1; afirst supply member 13, which is connected to the first liquid supplypart 11 via a supply pipe 11A that has a passageway, that comprises asupply port 13A that supplies the liquid 1 fed from this first liquidsupply part 11 to the substrate P; and a second supply member 14, whichis connected to the second liquid supply part 12 via a supply pipe 12Athat has a passageway, that comprises a supply port 14A that suppliesthe liquid 1 fed from this second liquid supply part 12 to the substrateP. The first and second supply members 13, 14 are disposed proximate tothe front surface PA of the substrate P, and are provided at positionsthat are mutually different in directions within the plane of thesubstrate P. Specifically, the first supply member 13 of the liquidsupply mechanism 10 is provided in one of the scanning directions (−Xdirection) with respect to the projection area AR1, and the secondsupply member 14 is provided in the other direction (+X direction).

Each of the first and second liquid supply parts 11, 12 comprises, forexample, a tank that stores the liquid 1 and a pressure pump, andsupplies the liquid 1 to the substrate P through the supply pipes 11A,12A and the supply members 13, 14. In addition, the liquid supplyoperation of the first and second liquid supply parts 11, 12 iscontrolled by the control apparatus CONT, which is capable ofindependently controlling the amount of liquid 1 supplied by the firstand second liquid supply parts 11, 12 to the substrate P per unit oftime. In addition, each of the first and second liquid supply parts 11,12 comprises a liquid temperature adjusting mechanism and supplies thesubstrate P with the liquid 1, which has a temperature that issubstantially the same as the temperature (e.g., 23° C.) inside thechamber that houses the apparatus.

The liquid recovery mechanism 20 recovers the liquid 1 on the substrateP and comprises: first and second recovery members 23, 24 that compriserecovery ports 23A, 24A, respectively, that are disposed proximate tothe front surface PA of the substrate P; and first and second liquidrecovery parts 21, 22, which are respectively connected to these firstand second recovery members 23, 24 via recovery pipes 21A, 22A, whichhave passageways. Each of the first and second liquid recovery parts 21,22 comprises, for example, a suction apparatus (e.g., a vacuum pump) anda tank that stores the recovered liquid 1; further, these first andsecond liquid recovery parts 21, 22 recover the liquid 1 on thesubstrate P via the first and second recovery members 23, 24 and therecovery pipes 21A, 22A. The liquid recovery operation of the first andsecond liquid recovery parts 21, 22 is controlled by the controlapparatus CONT, which is capable of controlling the amount of liquid 1recovered by the first and second liquid recovery parts 21, 22 per unitof time.

FIG. 5 is a plan view that schematically depicts the constitution of theliquid supply mechanism 10 and the liquid recovery mechanism 20. Asdepicted in FIG. 5, the projection area AR1 of the projection opticalsystem PL is set to a slit shape (rectangular shape), wherein thelongitudinal directions are in the Y axial directions (the non-scanningdirections), and are formed on a part of the substrate P so that theimmersion area AR2, which is filled with the liquid 1, includes theprojection area AR1. Furthermore, the first supply member 13 of theliquid supply mechanism 10, which is for forming the immersion area AR2of the projection area AR1, is provided in one of the scanningdirections (−X direction) with respect to the projection area AR1, andthe second supply member 14 is provided in the other direction (+Xdirection).

The first and second supply members 13, 14 are formed substantiallyarcuately in a plan view, and are set so that their supply ports 13A,14A are at least as large in the Y axial directions as the projectionarea AR1 in the Y axial directions. Furthermore, the supply ports 13A,14A, which are formed substantially arcuately in a plan view, aredisposed so that the projection area AR1 is interposed therebetween inthe scanning directions (the X axial directions). The liquid supplymechanism 10 supplies the liquid 1 to both sides of the projection areaAR1 simultaneously via the supply ports 13A, 14A of the first and secondsupply members 13, 14.

The first and second recovery members 23, 24 of the liquid recoverymechanism 20 respectively comprise recovery ports 23A, 24A, which arearcuately and continuously formed so that they face the front surface PAof the substrate P. Furthermore, the first and second recovery members23, 24, which are disposed so that they face one another, form asubstantially annular recovery port The recovery ports 23A, 24A of thefirst and second recovery members 23, 24 are disposed so that theysurround the first and second supply members 13, 14 of the liquid supplymechanism 10 as well as the projection area AR1. In addition, aplurality of partition members 25 are provided inside the recovery ports23A, 24A, which are continuously formed so that they surrounds theprojection area AR1.

The liquid 1 supplied to the substrate P from the supply ports 13A, 14Aof the first and second supply members 13, 14 is supplied so that itspreads between the substrate P and the lower end surface at the tippart (optical element 2) of the projection optical system PL. Inaddition, the liquid 1 that flows to the outer side of the first andsecond supply members 13, 14 with respect to the projection area AR1 isrecovered by the recovery ports 23A, 24A of the first and secondrecovery members 23, 24, which are disposed on the outer side of thefirst and second supply members 13, 14 with respect to the projectionarea AR1.

When performing a scanning exposure of the substrate P in the presentembodiment, the amount of liquid 1 supplied per unit of time from thenear side of the projection area AR1 in the scanning directions is setlarger than that on the opposite side thereof. For example, if theexposure process is performed while moving the substrate P in the +Xdirection, the control apparatus CONT sets the amount of liquid 1supplied from the −X side of the projection area AR1 (i.e., from thesupply port 13A) greater than that from the +X side (i.e., from thesupply port 14A); on the other hand, when performing the exposureprocess while moving the substrate P in the −X direction, the amount ofliquid 1 supplied from the +X side of the projection area AR1 is setgreater than that from the −X side. In addition, with respect to thescanning directions, the amount of liquid 1 recovered per unit of timeon the near side of the projection area AR1 is set less than that on theopposite side. For example, when moving the substrate P in the +Xdirection, the amount of liquid 1 recovered from the +X side of theprojection area AR1 (i.e., by the recovery port 24A) is greater thanthat from the −X side (i.e., by the recovery port 23A).

FIG. 6 is a plan view of the substrate table 52 of the substrate stagePST, viewed from above. A movable mirror 55 is disposed at two mutuallyperpendicular edge parts of the substrate table 52, which isrectangularly shaped in a plan view. A fiducial mark FM, which is usedwhen aligning the mask M and the substrate P with respect to aprescribed position, is provided in the vicinity of the part where themovable mirrors 55, 55 intersect. In addition, though they are notshown, various sensors, such as luminous flux intensity sensors, areprovided around the substrate P on the substrate stage PST.

In addition, the recessed part 32, which is circular in a plan view, ifformed at the substantially center part of the substrate table 52, and asupport part 52 a is protrudingly provided to this recessed part 32 inorder to support the substrate holder PH, as shown in FIG. 7.Furthermore, the substrate holder PH, which holds the substrate P, isdisposed inside the recessed part 32 in a state wherein the substrateholder PH is supported by the support part 52 a, and wherein there is agap between the substrate holder PH and the substrate table 52.Furthermore, the pressure in the gap between the substrate table 52 andthe substrate holder PH is set to atmospheric pressure (open).Furthermore, the plate part 30, which has the flat surface 31 (flatpart) that is at a height substantially the same as the front surface PAof the substrate P, is provided integrally with the substrate table 52around the substrate P.

In the present embodiment, among the surfaces of the substrate holderPH, the upper end surfaces of the circumferential wall part 33, thesupport parts 34 and the rib shaped support parts 7, as well as a sidesurface 37 are liquid repellent. Liquid repellency treatments (waterrepellency treatments) for the substrate holder PH include coating itwith a fluororesin material or a liquid repellent material, such asacrylic resin material, or adhering a thin film consisting of theabovementioned liquid repellent material. Liquid repellent materialsused to impart liquid repellency include materials that are insoluble inthe liquid 1.

The substrate table 52 (plate part 30) comprises a side wall part 73that forms the recessed part 32. The side wall part 73 is formed so thatit is spaced apart from the substrate holder PH by a gap C, i.e., it hasa shape that planarly overlaps (the outer circumference of) thesubstrate P, which is held by the flat surface 31, by a width B. Theupper surface of the side wall part 73 is a circle of a size that, in aplan view, is spaced apart from the outer circumference (side surfacePB) of the substrate P by a gap A (e.g., 0.3 to 0.5 mm), and comprises aliquid repellent surface 72 that, in a cross sectional view, opposes theouter circumferential part of the rear surface PC of the substrate P,which is held by the substrate holder PH. The liquid repellent surface72 is formed at a position at which it does not contact the rear surfacePC of the substrate P and is spaced apart therefrom by a gap of, forexample, 0.2 mm (namely, at a depth of the thickness of the substrate P+0.2 mm from the flat surface 31).

The front surface PA, which is the exposure surface of the substrate P,is coated with a photoresist 90 (photosensitive material). In thepresent embodiment, the photosensitive material 90 is a photosensitivematerial (e.g., TARF-P6100 manufactured by Tokyo Ohka Kogyo Co., Ltd.)for ArF excimer laser light, is liquid repellent (water repellent), andhas a contact angle of approximately 70 to 80°.

In addition, in the present embodiment, the side surface PB of thesubstrate P is given liquid repellency treatment (water repellencytreatment). Specifically, the side surface PB of the substrate P is alsocoated with the abovementioned liquid repellent photosensitive material90. Furthermore, the rear surface PC of the substrate P is also givenliquid repellency treatment by coating it with the abovementionedphotosensitive material 90.

Furthermore, part of the surface of the substrate table 52 (substratestage PST) is given liquid repellency treatment and is therefore liquidrepellent In the present embodiment, the flat surface 31 of thesubstrate table 52 (plate part 30), the liquid repellent surface 72, anda step part 36 therebetween are all liquid repellent. The same treatmentthat is given to the substrate holder PH is also used for the liquidrepellency treatment of the substrate table 52 (plate part 30).Furthermore, the substrate table 52 may be formed from a liquidrepellent material (e.g., fluororesin).

In addition, the substrate stage PST comprises a recovery apparatus 60that suctions and recovers the liquid 1 that flows into a second space39 (which is formed by the step part 36, the side surface PB of thesubstrate P, and the liquid repellent surface 72) that communicates withthe portion that opposes the rear surface PC of the substrate P. In thepresent embodiment, the suction apparatus 60 comprises: a tank 61 thatis capable of storing the liquid 1; a passageway 62, which is providedinside the substrate table 52, that connects the space 39 and the tank61; and a pump 64 that is connected to the tank 61 via a valve 63.Furthermore, liquid repellency treatment is also given to an inner wallsurface of the passageway 62.

The following explains the method by which the exposure apparatus EXthat has the constitution discussed above performs immersion exposure ofan edge area E of the substrate P.

As shown in FIG. 7, when performing immersion exposure of the edge areaE of the substrate P, the liquid 1 of the immersion area AR2 is disposedat part of the front surface PA of the substrate P and at part of theflat surface 31 of the plate part 30. At this time, the negativepressure suction force from the suction apparatus 40 does not act uponthe substrate P at the circumferential wall part 33; however, thesubstrate P is linearly supported by the rib shaped support parts 7,which extend from the circumferential wall part 33 to the support parts34 in the vicinity of the circumferential wall part 33, and the negativepressure suction force acts upon the surroundings of the support parts7; consequently, the negative pressure suction force does not causewarpage and the like, and the substrate P can be supported withsatisfactory flatness.

Consequently, it is possible to correct for waviness within theprojection area AR1, which is set by the exposure slit ES discussedabove, and to keep flatness in the projection area AR1 within aprescribed value by driving the substrate table 52 via the substratestage drive apparatus PSTD to control the position of the substrate P inthe Z axial directions as well the front surface position in the θX andθY directions. As a result, the pattern of the mask M can be projectedonto a flat substrate P via the projection optical system PL and theliquid 1, and a high resolution pattern can thereby be formed on thesubstrate P.

Herein, because the side surface PB of the substrate P and the step part36 that opposes such are given liquid repellency treatment and becausethe gap therebetween is not large, as shown in FIG. 7, it is difficultfor the liquid 1 of the immersion area AR2 to infiltrate the gap A andvirtually no liquid 1 flows therein as a result of the surface tensionof the liquid 1. In addition, if the liquid 1 infiltrates the secondspace 39 from the gap A, both the rear surface PC of the substrate P andthe liquid repellent surface 72 are liquid repellent and the gap betweenthe rear surface PC and the liquid repellent surface 72 is minute;therefore, it is difficult for the liquid 1 that has infiltrated thesecond space 39 to infiltrate this gap and virtually none of the liquid1 flows from that gap to the recessed part 32 as a result of the surfacetension thereof. Furthermore, the liquid 1 that flows into the secondspace 39 is suctioned and recovered (refer to FIG. 4) by the recoveryapparatus 60 into the tank 61 via the passageway 62 with a timing, suchas when the substrate is replaced, that does not cause interference,even if vibrations attendant with suctioning are transmitted to thesubstrate P. The tank 61 is provided with a discharge passageway 61A,and the liquid 1 is discharged from the discharge passageway 61A if aprescribed amount has accumulated.

At this time, even if the liquid 1 reaches the substrate holder PH byway of, for example, the rear surface PC of the substrate P, warpage ofthe substrate P is suppressed, it is possible to reliably prevent theinfiltration of the liquid 1 into the suction space 38 via thecircumferential wall part 33 and the rib shaped support parts 7 becausethe upper end surfaces of the circumferential wall part 33 and the ribshaped support parts 7 are given liquid repellency treatment, and thus astabler exposure process can be performed. In addition, because theupper end surfaces of the circumferential wall part 33, the rib shapedsupport parts 7, and the support parts 34 are given liquid repellencytreatment, even if the liquid 1 scatters and adheres to these upper endsurfaces during, for example, the replacement of the substrate P, it ispossible to easily eliminate the liquid 1 on the upper end surfaces bymeasures such as blowing air, and thereby prevent such from adverselyaffecting the vacuum chucking of the substrate after that replacement.

Furthermore, the substrate holder PH of the abovementioned embodiment isconstituted so that one end of each of the rib shaped support parts 7 isconnected to the circumferential wall part 33, but the present inventionis not limited thereto, and the rib shaped support parts 7 may bedisposed so that they are spaced apart from the circumferential wallpart 33 by a gap.

In addition, the substrate stage PST of the abovementioned embodiment isconstituted so that the substrate holder PH and the substrate table 52are separately provided, but the present invention is not limitedthereto, and they can also be formed integrally. Namely, the substratetable 52 can also be constituted so that it is made to function as thesubstrate holder. In this case, movable mirrors are not provided on thesubstrate table 52, which is the substrate holder, and, as shown in FIG.8, the end surfaces of the substrate table 52 that oppose the laserinterferometers 56 can be made to be reflecting surfaces 55A (reflectingparts). This constitution can reduce the number of parts and costs, andcan also eliminate errors in mounting the movable mirrors, which makesit possible to improve the measurement accuracy of the laserinterferometers when they measure the substrate table 52 (i.e., thesubstrate P).

The liquid 1 in each of the abovementioned embodiments comprises purewater. Pure water is advantageous because it can be easily obtained inlarge quantities at, for example, a semiconductor fabrication plant, anddoes not adversely impact, for example, the optical element (lens) andthe photoresist on the substrate P. In addition, because pure water hasno adverse impact on the environment and has an extremely low impuritycontent, it can also be expected to have the effect of cleaning thefront surface of the substrate P and the surface of the optical elementprovided to the tip surface of the projection optical system PL.

Furthermore, PFPE (perfluorinated polyether) may be used as the liquid1.

Further, because the refractive index n of pure water (water) withrespect to the exposure light EL that has a wavelength of approximately193 nm is substantially 1.44, if an ArF excimer laser (193 nmwavelength) is used as the light source of the exposure light EL, thenthe wavelength of the light on the substrate P would shorten by amultiple of 1/n, i.e., to approximately 134 nm, thereby obtaining a highresolution. Furthermore, because the depth of focus will increaseapproximately n times, i.e., approximately 1.44 times, that of in air,the numerical aperture of the projection optical system PL can befurther increased if it is preferable to ensure a depth of focus that isapproximately the same as that when used in air, and the resolution isalso improved from this standpoint.

Furthermore, the substrate P in each of the abovementioned embodimentsis not limited to a semiconductor wafer for fabricating semiconductordevices, and is also applicable to, for example, a glass substrate for adisplay device, a ceramic wafer for a thin film magnetic head, and amask or the original plate of a reticle (synthetic quartz, siliconwafer) used by an exposure apparatus.

The exposure apparatus EX can also be adapted to a step-and-scan typescanning exposure apparatus (scanning stepper) that scans and exposesthe pattern of the mask M by synchronously moving the mask M and thesubstrate P, as well as to a step-and-repeat type projection exposureapparatus (stepper) that performs a full field exposure of the patternof the mask M with the mask M and the substrate P in a stationary state,and sequentially steps the substrate P. In addition, the presentinvention can also be adapted to a step-and-stitch type exposureapparatus that partially and superposingly transfers at least twopatterns onto the substrate P. Furthermore, the present invention canalso be adapted to an exposure apparatus, wherein a projection opticalsystem PL projects a spot light to expose the substrate P with apattern, without using the mask M.

In addition, the present invention can also be adapted to a twin stagetype exposure apparatus as disclosed in, for example, JapaneseUnexamined Patent Application, Publication No. H10-163099, JapaneseUnexamined Patent Application, Publication No. H10-214783, and PublishedJapanese Translation No. 2000-505958 of the PCT InternationalPublication.

The type of exposure apparatus EX is not limited to semiconductor devicefabrication exposure apparatuses that expose the pattern of asemiconductor device on the substrate P, but can also be widely adaptedto exposure apparatuses for fabricating liquid crystal devices ordisplays, and exposure apparatuses for fabricating, for example, thinfilm magnetic heads, imaging devices (CCDs), or reticles and masks.

If a linear motor is used in the substrate stage PST or the mask stageMST (refer to U.S. Pat. No. 5,623,853 and U.S. Pat. No. 5,528,118), theneither an air levitation type that uses an air bearing, or a magneticlevitation type that uses Lorentz's force or reactance force may beused. In addition, each of the stages PST, MST may be a type that movesalong a guide or may be a guideless type.

For the drive mechanism of each of the stages PST, MST, a planar motormay be used wherein a magnet unit, in which magnets are arranged twodimensionally, and an armature unit, in which coils are arranged twodimensionally, are opposed to one another, and each of the stages PST,MST are driven by electromagnetic force. In this case, any one of themagnet unit and the armature unit is connected to the stages PST, MSTand the other one should be provided on the moving surface side of thestages PST, MST.

The reaction force generated by the movement of the substrate stage PSTmay be mechanically discharged to the floor (ground) by using a framemember so that it is not transmitted to the projection optical systemPL, as recited in Japanese Unexamined Patent Application, PublicationNo. H08-166475 (U.S. Pat. No. 5,528,118).

The reaction force generated by the movement of the mask stage MST maybe mechanically discharged to the floor (ground) by using a frame memberso that it is not transmitted to the projection optical system PL, asrecited in Japanese Unexamined Patent Application, Publication No.H08-330224 (U.S. Pat. No. 5,874,820). In addition, the reaction forcemay be counteracted by using the law of conservation of momentum, asrecited in Japanese Unexamined Patent Application, Publication No.8-63231 (U.S. Pat. No. 6,255,796).

The exposure apparatus EX of the embodiments in the present applicationis manufactured by assembling various subsystems, including eachconstituent element recited in the claims of the present application, sothat prescribed mechanical electrical, and optical accuracies aremaintained. To ensure these various accuracies, adjustments areperformed before and after this assembly, including an adjustment toachieve optical accuracy for the various optical systems, an adjustmentto achieve mechanical accuracy for the various mechanical systems, andan adjustment to achieve electrical accuracy for the various electricalsystems. The process of assembling the exposure apparatus from thevarious subsystems includes the mutual mechanical connection of thevarious subsystems, the wiring and connection of electrical circuits,the piping and connection of the atmospheric pressure circuit, and thelike. Naturally, before the process of assembling the exposure apparatusfrom these various subsystems, there are also the processes ofassembling each individual subsystem. When the process of assembling theexposure apparatus from the various subsystems is finished, acomprehensive adjustment is performed to ensure the various accuraciesof the exposure apparatus as a whole. Furthermore, it is preferable tomanufacture the exposure apparatus in a clean room wherein, for example,the temperature and the cleanliness level are controlled.

As shown in FIG. 9, a micro-device, such as a semiconductor device, ismanufactured by: a step 201 that designs the functions and performanceof the micro-device; a step 202 that fabricates a mask M (reticle) basedon this design step; a step 203 that fabricates a substrate P (wafer),which is the base material of the device; a wafer processing step 204wherein the exposure apparatus EX of the embodiments discussed aboveexposes a pattern of the mask M onto the substrate P (wafer); a deviceassembling step 205 (including a dicing process, a bonding process, anda packaging process); an inspecting step 206; and the like.

1. A substrate holder that comprises: a circumferential edge part thatsurrounds a suction space; and a first support part that is provided inthe suction space and that supports a substrate; comprising: a secondsupport part that extends from the circumferential edge part to thefirst support part and that supports the substrate.
 2. A substrateholder according to claim 1, wherein a plurality of the second supportparts is provided, the lengths of which extend from the circumferentialedge part to the first support part and vary.
 3. A substrate holderaccording to claim 1, wherein the support surface area whereon thesubstrate is supported by the second support part is larger than thesupport surface area whereon the substrate is supported by the firstsupport part.
 4. A substrate holder according to claim 1, wherein aplurality of the first support parts is provided.
 5. A substrate holderaccording to claim 1, wherein the first support parts constitute a pinchuck.
 6. A substrate holder according to claim 1, wherein at least oneof the first support part and the second support part is given waterrepellency treatment.
 7. A substrate holder according to claim 1,wherein the second support part is made of a ceramic material.
 8. Asubstrate holder according to claim 1, wherein the second support partis radially provided.
 9. A substrate holder according to claim 1,wherein the circumferential edge part and the second support part areformed integrally.
 10. A substrate holder according to claim 1, whereinthe height of the first support part is the same as the height of thesecond support part.
 11. A substrate holder according to claim 9,wherein the height of the first and second support parts is the same asthe height of the circumferential edge part.
 12. A stage apparatus thatholds and moves a substrate, comprising: a substrate holder, whichserves as a substrate holder that holds the substrate, according toclaim
 1. 13. A stage apparatus according to claim 12, wherein areflecting part is provided to an end surface of the substrate holder.14. An exposure apparatus that uses a stage apparatus to expose asubstrate with a pattern, wherein a stage apparatus according to claim12 is used as the stage apparatus.
 15. An exposure apparatus accordingto claim 14, wherein exposure is performed in a state wherein a liquidis filled between the substrate and a projection optical system, whichprojects the pattern onto the substrate.